The invention relates to compositions containing texturized fibrous materials prepared from cellulosic and/or lignocellulosic materials, including but not limited to poly-coated paper, and a matrix material.
Cellulosic and lignocellulosic materials are produced, processed, and used in large quantities in a number of applications. Once used, these fibers are usually discarded as waste materials. As a result, there is an ever-increasing amount of waste cellulosic and lignocellulosic fiber. Paper coated with a polymer (poly-coated paper) is used in a number of applications. For example, poly-coated paper is used to make a variety of food containers, including juice cartons and boxes for frozen foods.
The invention is based on the discovery that texturized cellulosic and/or lignocellulosic materials can be combined with many different matrix materials, including organic matrices (e.g., thermosetting resins, elastomers, asphalts, lignins, or tars) to produce useful compositions.
In one embodiment, the invention features a composition that includes a matrix reinforced with at least about 2% fiber (e.g., 2%, 5%, 10%, 30%, 50%, 70%, 90% or more, e.g., 10 to 90%, e.g., 30 to 70%), where the fiber is a lignocellulosic or cellulosic material that has been sheared to the extent that the internal fibers are substantially exposed. Material thus sheared is termed xe2x80x9ctexturized.xe2x80x9d At least 5% (e.g., 5% 10%, 5%, 10%, 25%, 50%, 75%, 90%, 95%, 99%, or substantially all) of the material by weight can be texturized. Generally, at least about 5% or 10%, more preferably at least about 25%, 50%, or 70%, of these fibers have a length/diameter (L/D) ratio of at least 5, more preferably at least 10 or 25, or at least 50.
The matrix can include, for example, a thermosetting resin (e.g., an alkyd, a diallyl phthalate, an epoxy, a melamine, a phenolic, a silicone, a urea, a thermosetting polyester, or their derivatives, or a combination of two or more such thermoplastic resins), an elastomer (e.g., natural rubber, isoprene rubber, styrene-butadiene copolymers, neoprene, nitrile rubber, butyl rubber, ethylene propylene copolymer (xe2x80x9cEPMxe2x80x9d), ethylene propylene diene terpolymer (xe2x80x9cEPDMxe2x80x9d), hypalon, acrylic rubber, polysulfide rubber, silicones, urethanes, fluoroelastomers, butadiene, or epichlorohydrin rubber, or combinations or derivatives thereof), a tar or asphalt, or a lignin (e.g., lignins that have been extracted and/or isolated and/or purified from their natural sources, or synthetic or modified lignins and their derivatives). The matrix can be prepared from natural or synthetic components, or combinations of both.
The composition can also include optional additives such as pharmaceuticals; agricultural compounds; enzymes; particulate, powdered, or granulated solids; plant seeds; foodstuffs (e.g., for human consumption or animal feed); bacteria; and/or additives such as calcium carbonate, graphite, asbestos, wollastonite, mica, glass, fiber glass, chalk, talc, silica, ground construction waste, tire rubber powder, carbon fibers, metal fibers, plasticizers, lubricants, antioxidants, opacifiers, heat stabilizers, colorants, impact modifiers, photostabilizers, biocides, antistatic agents, organic or inorganic flame retardants, biodegradation agents, dispersants, emulsion polymers, accelerators, extenders, retardants, antifoaming agents, thixotropic agents, or waterproofing agents. In some cases, such additives can constitute from about 0.5% to about 20% (e.g., 0.5%, 1%, 2%, 5%, 10%, 15%, or 20%), or more, of the total weight of the composition.
The composition can be in a bulk form, or can be in the form of articles such as pipes, panels, decking materials, boards, housings, sheets, blocks, bricks, pebbles, stones, poles, straps, fencing, members, doors, shutters, awnings, shades, signs, frames, window casings, backboards, flooring, tiles, railroad ties, forms, trays, tool handles, stalls, bedding, dispensers, staves, films, wraps, tapes, bands, totes, barrels, boxes, packing materials, baskets, straps, slips, racks, casings, binders, dividers, walls, indoor and outdoor carpets, rugs, woven goods, mats, frames, bookcases, sculptures, chairs, tables, desks, art, toys, games, pallets and other materials handling systems, wharves, piers, boats, masts, pollution control products, gravel, paving materials, road beds, swimming pools, septic tanks, automotive panels, substrates, computer housings, above- and below-ground electrical casings, furniture, picnic tables, tents, playgrounds, benches, shelters, sporting goods, beds, bedpans, thread, filament, cloth, plaques, trays, hangers, servers, pools, insulation, caskets, book covers, clothes, canes, crutches, and other construction, agricultural, material handling, transportation, automotive, industrial, environmental, naval, electrical, electronic, recreational, medical, textile, and consumer products, rubber hoses, marine products, pipes, or polymeric foams.
The term xe2x80x9ctexturized fibrous materialxe2x80x9d, as used herein, refers to cellulosic or lignocellulosic material that has been sheared to the extent that its internal fibers are substantially exposed. Generally, at least about 10%, more preferably at least about 25%, 50%, or 70%, of these fibers have a length/diameter (L/D) ratio of at least 5, more preferably at least 10 or 25, or at least 50. An example of texturized fibrous newsprint is shown in FIG. 1. An example of texturized poly-coated paper is shown in FIG. 2.
The term xe2x80x9cmatrixxe2x80x9d, as used herein, refers to the continuous phase of the compositions described herein and can include, for example, thermoplastic resins, thermosetting resins, elastomers, tars, lignins, or asphalts, or mixtures of any of these or other materials. Other components (e.g., contaminants, metal filings) may also be present in the matrix.
The term xe2x80x9cthermosetting resinxe2x80x9d, as used herein, refers to plastics (e.g., organic polymers) that are cured, set, or hardened into a permanent shape. Curing is an irreversible chemical reaction typically involving molecular cross-linking using heat or irradiation (e.g., UV irradiation). Curing of thermosetting materials can be initiated or completed at, for example, ambient or higher temperatures. The cross-linking that occurs in the curing reaction is brought about by the linking of atoms between or across two linear polymers, resulting in a three-dimensional rigidified chemical structure.
Examples of thermosetting resins include, but are not limited to, silicones, alkyds, diallyl phthalates (allyls), epoxies, melamines, phenolics, certain polyesters, silicones, ureas, polyurethanes, polyolefin-based thermosetting resins such as TELENE(trademark) (BF Goodrich) and METTON(trademark) (Hercules).
The term xe2x80x9celastomerxe2x80x9d, as used herein, refers to macromolecular materials that rapidly return to approximate their initial dimensions and shape after deformation and subsequent release.
Examples of elastomers include, but are not limited to, natural rubber, isoprene rubber, styrene-butadiene copolymers, neoprene, nitrile rubber, butyl rubber, ethylene propylene copolymer (i.e., xe2x80x9cEPMxe2x80x9d) and ethylene propylene diene terpolymer (i.e., xe2x80x9cEPDMxe2x80x9d), hypalon, acrylic rubber, polysulfide rubber, silicones, urethanes, fluoroelastomers, butadiene, and epichlorohydrin rubber.
The term xe2x80x9ctarxe2x80x9d, as used herein, means a typically thick brown to black liquid mixture of hydrocarbons and their derivatives obtained by distilling wood, peat, coal, shale, or other vegetable or mineral materials. An example is coal tar, which is made by destructive distillation of bituminous coal or crude petroleum (e.g., containing naphthalene, toluene, quinoline, aniline, and cresols).
The term xe2x80x9cligninxe2x80x9d, as used herein, refers to an amorphous substance, mixture, or powder isolated from wood, plants, recycled wood or plant products, or as a byproduct of paper making. In nature, lignins, together with cellulose, form the woody cell walls of plants and the cementing material between them. They are typically polymeric and may be distinguished from cellulose by (1) a higher carbon content than cellulose, and (2) the inclusion of propyl-benzene units, methoxyl groups, and/or hydroxyl groups. They are generally not hydrolyzed by acids but may be soluble in hot alkali and bisulfite, and may be readily oxidizable. Lignins can be recovered from the liquor that results from the sulfate or soda process of making cellulosic pulp, or from sulfite liquor. The term lignin thus includes sulfite lignin, or lignin-sulfonates.
The term xe2x80x9casphaltxe2x80x9d, as used herein, refers, for example, to an amorphous, solid, or semisolid mixture of hydrocarbons, brownish-black pitch, or bitumen, produced from the higher-boiling point minerals oils by the action of oxygen. Asphalts include both asphaltenes and carbenes. Asphalts are commonly used for paving, roofing, and waterproofing materials.
The new compositions have properties that render them useful for various applications. Compositions that include texturized fibrous material and matrices are, for example, strong, lightweight, and inexpensive.
Other advantages afforded by the texturized fibers include:
(1) Reduced densities of matrix materials such as elastomers and thermosetting resins.
(2) Higher impact resistance due to increased interfacial area between matrix and texturized fiber and increased energy absorbed when texturized fiber delaminates from matrices.
(3) Reduced surface friction.
(4) Higher lubricity surfaces.
(5) Enhanced tolerance for and compatibilization of both the hydrophobic and hydrophilic constituents in the matrices.
(6) Enhanced ability to custom tailor the properties of the composition for specific requirements.
Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.